Coal has the main composition of carbon , and carbon in a nature make a chemical reaction to build their substances. These substances are varying and have their own name depend on the composition on their chain. Carbon in their chemical chain usually called as carbonates that have many name of these substances . The mineral that usually available on coal are as follows: Silicates: Clay minerals: Kaolinite Al 2 Si 2 O 3 (OH) 4 Illite Montmorillonite Chlorite Mixed layer clays Others: Quartz SiO 2 Chalcedony SiO 2 Feldspar KAlSi 3 O 4 Tourmaline NaMg 3 Al 6 B 3 Si 6 O 27 (OH) 4 Sulphides: Pyrite FeS 2 Marcasite FeS 2 Sphalerite ZnS Galena PbS Carbonates: Calcite CaCO 3 Dolomite (CaMg)CO 3 Siderite FeCO 3 Aroganite CaCO 3 Ankerite (FeMgCa)CO 3 Dawsonite NaAlCO 3 (OH) 2 Strontianite SrCO 3 Sulphates: Gypsum CaSO 4 .2H 2 O Barite BaSO 4 Anhydrite CaSO 4 Coquimbite Fe 2 (SO 4 ) 2 .9H 2 O Szomolnokite NaFe 3 (SO 4 ) 2 (OH) 6 Other mine...